The functional decline in cardiovascular and metabolic reserve which occurs with advancing age may not be solely attributed to biological aging but may derive in part from the increasingly sedentary life style that accompanies aging. To determine the role of physical activity in preserving functional capacity, we have measured body composition, maximal aerobic capacity (VO2max), cardiac volumes at rest, during maximal bicycle exercise and lower body negative pressure, blood lipids and glucose tolerance in 19 highly trained men (T) aged 60-76 years. A comparison with 11 healthy lean sedentary controls (C) is shown below. T C P Age 65 +/- 1 65 +/- 2 NS % body fat 14 +/- 1 15 +/- 1 NS VO2max (ml/kg/min) 51 +/- 1 30 +/- 2 less than .01 LDL cholesterol (mg/dl) 117 +/- 5 129 +/- 10 NS HDL cholesterol (mg/dl) 59 +/- 3 49 +/- 3 less than .05 Triglycerides 76 +/- 4 112 +/- 10 NS Fasting glucose (mg/dl) 93 +/- 2 98 +/- 2 less than .05 2 hr postprandial glucose (mg/dl) 104 +/- 6 124 +/- 3 less than .05 Mean +/- SEM Thus in older men, high levels of physical activity appear to attenuate age-related declines in cardiovascular and metabolic function.